Multiple automatic circuit breaker



ALFRED E. MAIER I5 Sheets-Sheet 1 P2 M i .'r. M. COLE ETAL MULTIPLE AUTQMA'IIC CIRCUIT BREAKER Filed'maroh 20, 1959 March 17, 1964 T. M. COLE ETAL MULTIPLE AUTOMATIC CIRCUIT BREAKER Filed March 2o, A195s March 17, 1964 5 Sheets-Sheet 2 INV ENTORS TL/V ATTORNEY 5 Sheets-Sheet 3 March 17, 1964 T. M. coLE ETAL MULTIPLE AUTOMATIC CIRCUIT BREAKER Filed vMaJGl'l 20, 1959 2.,.) /M//Mluw INVENTORS THOMAS M. COLE ALFRED E MAIER United States Patent O 3,125,653 MULTIPLE AUTOMATIC CIRCUIT BREAKER Thomas M. Cole, Harrison, N.Y., and Alfred E. Maier,

Colonia, NJ., assignors to Federal Paciiic Electric Company, a corporation of Delaware Filed Mar. 20, 1959, Ser. No. 800,808 20 Claims. (Cl. 200-116) This invention relates generally to circuit breakers and, more particularly, to multi-pole circuit breakers which are normally operable to open or close the circuit and which operate automatically to open the circuit upon the occurrence of an overload or short circuit condition.

In a conventional type of multi-pole circuit breaker to which the invention is applicable a single common actuating mechanism is provided for the movable contact members of the multiple poles which are interconnected for simultaneous actuation, and the Contact pressures obtainable at the contact members is a function of such actuating mechanism which has prescribed limitations. The actuating mechanism in this type of circuit breaker includes a cradle which is releasably latched by the trip mechanism of the breaker. The trip mechanism is thus relied upon to produce a substantial reaction force that is related to the force of the actuating mechanism tending to open the contact members and to the force of the actuating mechanism that closes the contacts and builds up heavy resilient contact pressure in the closing operation. Only a fraction of the reaction force provided by the actuating mechanism is actually imposed on the trip mechanism, but that imposed fraction has its practical minimum limits.

One important object of the present invention is the provision of a compact circuit breaker of high rating having a novel actuating organization for achieving the heavy Contact pressures desirable in such a breaker. A related object resides in the provision of such a circuit breaker without imposing undue force on the trip mech anism. Another important object or" the invention resides in the provision of increased drive for fast opening of the contacts of a multi-pole circuit breaker, and a related object resides in the provision of means for developing heavier and more uniformly distributed pressure among the respective contacts of the multiple poles.

Pursuant to these objects of the present invention, the illustrative embodiment described in detail below utilizes plural actuating mechanisms physically disposed in association with the contacts of different poles to operate the movable contact members of all the poles. The movable contacts of those poles are interconnected in a highly effective manner to distribute the contact-closing force among all the poles and thereby to develop more nearly equal pressures at the respective resiliently-backed contacts, and for opening of the contacts in unison. The related eaturefof the invention resides in the provision of multiple releasable actuating mechanisms, physically separated and each of smail proportions, and of coordinating means for the independently releasable parts of such separate actuating mechanisms so as to be controllable by a single trip bar in a multi-pole circuit breaker. A further object resides in the provision of means for reducing the total force imposed by the releasable mechanisms on the trip mechanism so that no more force is imposed on the trip mechanism than that actually desired for operation thereof.

Only a small fraction of the force of the actuating mechanisms tending to release the contact members and applied by their cradles is transmitted to the trip mechanism. More particularly, the only force imposed by the plural actuating mechanisms on the trip mechanism is a torsion force of low magnitude required to operate the trip mechanism While the remainder of the cradle- 3,125,653 Patented Mar. 17, 1964 ICC restraining force is absorbed in the frames of the actuating mechanisms. Though the trip mechanism has a single output point the plural cradles of the actuating mechanisms are controlled for release in unison in response to predetermined overload conditions in the circuit through any pole of the breaker.

Another object of the present invention is the provision of an improved tripping arrangement in multi-pole circuit breakers.

Yet another object of the present invention is the provision of a generally improved compact breaker of high rating which is of unique design and construction and which is eminently suitable for its intended purposes.

The above and other objects, features and advantages of the present invention will be more fully understood from the following description considered in connection with the accompanying illustrative drawings in which:

FIG. l is a top plan View of a multi-pole circuit breaker formed according to the present invention, with the cover shown removed;

FIG. 2 is a sectional view taken on the line 2 2 of FIG. l;

FIG. 3 is a sectional View taken on the line 33 of FIG. 1;

FIG. 4 is a vertical sectional view taken on the line 4-4 of FIG. l;

FIG. 5 is an enlarged vertical sectional view showing a portion of the tripping mechanism, said View being taken on the line 5-5 of FIG. l; and

FIG. 6 is an enlarged elevation of the tripping mechanism shown in FIG. 5, viewed from the left side thereof.

Referring to the drawings, and more particularly to FIGS. 1-3 thereof, there is shown a three-pole circuit breaker 10, each pole A, B, and C comprising a pair of terminals l2 and 14 disposed at opposite ends of the breaker. The circuit breaker includes a base 16 of molded insulating material on which the components of the breaker mechanism are mounted. A cover 18 of molded insulating material is removably secured to the base 16 and cooperates therewith to form an enclosing housing for the breaker mechanism. The circuit breaker is provided at each pole with two associated pairs of stationary and movable main contacts 20 and 22, respectively, an associated pair of stationary and movable arcing contacts 24 and 26, respectively, and an arc chute 28 having a number of arc splitter plates 25. Each of the movable main contacts 22 is mounted on a contact block 30 and the movable arcing contact 26 is mounted on arcing contact block 32 having an arcing tip 34 extending into arc chute 28. Thus each pole is provided with a pair of blocks 30 and a block 32 disposed in side-by-side relation with the latter block disposed between the former blocks. The blocks 30 and 32 of each pole are pivotally mounted on a carrier 36 for the movable contacts by pivot pin 38, the latter extending through the spaced legs 40 of said contact carrier 36 and said blocks. The arcing contact block 32 is biased downwardly to bias contact 26 into pressure engagement with companion arcing contact 24 by compression spring 42 seated in fitting 44 secured to the base plate 46 of contact carrier 36. A threaded shaft 48 extends upwardly of the arcing block through` a suitable aperture provided therefor in plate 46 and receives a nut Si) which coacts with said plate to form a stop for limiting pivotal movement of the arcing block on contact opening. Contact pressure for each of the contact blocks 30 is developed by a compression spring 52 seated at one end in fitting 54 secured to plate 46. The opposite end of spring 52 is seated in a recess 56 of the contact block, the latter having a threaded shaft 53 extending upwardly therefrom through said spring. A nut 60 on shaft 58 forms a stop for limiting pivotal movement of the block 30 on contact opening.

The movable contact carrier 36 is pivotally mounted in a companion frame 62 by pivot pin 64 for movement between circuit open and closed positions. The three contact carriers 36 are operated by two actuating mechanisms indicated generally at 66 to be described in detail hereinafter. Each of the poles of the breaker is contained in a separate compartment formed by interphase barriers 68 and 68 in the base and cover which extend longitudinally of the breaker. The movable contact carriers 36 are rigidly interconnected for conjoint movement by the main tie or torque bar 70 and supplementary tie or torque bar 72, said bars being insulation covered and extending across all the poles of the breaker through barriers 68. The tie bars are suitably secured to the plates 46 of contact carriers 36 by brackets 74, 75. The tie bar 72 is secured to the contact carriers 36 remote from the pivotal mounting thereof to make the contact carrier assembly a more nearly rigid unit to obtain the desired equal distribution of the operating torque among the contact carriers 36.

Pursuant to the present invention, the outer poles A and C are each provided with actuating mechanism 66 for operating their companion contact members directly, the center pole being devoid of such actuating mechanism. Thus a pair of actuating mechanisms 66 provide drive for the three contact carriers 36, thus utilizing actuating mechanisms of modest proportions and avoiding an increase in the overall size of the breaker that would otherwise be entailed for a single actuating mechanism made more powerful to achieve the required heavy contact pressures. Furthermore, because theA center-pole carrier 36 is disposed between the other two carriers that do have actuating mechanisms and the tie bars 70 and 72 are relied on to apply operating torque to only the single centered carrier, the contact pressures are uniformly and efficiently developed. The actuating mechanisms 66 are alike,r each being of the overcenter spring quick` make and quick break type. Each mechanism 66 comprises a frame 76 suitably secured in the base 16, said frame having in-turned ilanges 78 which dene stopsfor the actuating member 80 of inverted U shape which is pivoted to said frame by pivot pins 82. The knee pin 84 interconnects the pair of upper links 86 and the lower T- shaped member 88 which extends through an opening 90 provided in the contact carrier 36, said member 88 being secured to the contact carrier by pivot pins 92. The links 86 at their opposite ends are pivotally connected to a releasable cradle 94 by pivot pin 9 6, the cradle beingv mounted on a shaft 98 that pivots in frame 76. A pair of tension springs 100 extend between knee pin 84 and the actuating member 80. The cradle 94 is providedj with a latch part 102 having an inclined face, which is latched by the trip mechanism to be described when the circuit breaker is closed. During both opening and closing operations of the circuit breaker manually the cradle remains latched. On circuit closing movement of the,

actuating member 80, the latter tensions springs 100 of the toggle and on overcentering of the springs the contact carrier 36 is actuated to closed position. 0n circuit opening movement of the actuating member 80 the toggle. collapses at the knee 84 to move contact carrier 36 to cir-V cuit open position. In a circuit closed condition,l they release of the cradle by the tripping mechanism results in rotation of the cradle about its pivot and overcentering of the springs, to break the toggle and open the circuit breaker.

The actuating members 80 of mechanisms 66are cou.- pled for conjoint actuation by the operating handle 104l which extends through opening 106 provided therefor at the center pole in the cover 18. The handle 104 has a bridging part 106provided with slots 108 for the reception of the coupling plates 110, the latter being securedv to said bridging part by screws 112. The two` plates 110 at each` end of the bridging part grips a leg 114 of a respective actuating member 80, so that operation of handle 104 will directly drive actuating members 80 in unison to actuate the coupled contact members 36 of each of the poles. If either mechanism 66 should start to over-center intinitesimally earlier than the other during a deliberately gradual operation, the tie bars nevertheless retard the opening operation of the rst mechanism and expedite opening ioperation of the second as soon as dead center is passed'.

The contacts 20 and 24 tare in circuit with terminal 12 through a contact plate 116. and the contact blocks 30 and 32 are electrically connected to the conductor 118 by conductors 12)` and 122, respectively (see FIG. 4), said conductor 118 being in circuit with terminal 15. It will be noted that the tie bar 72 carries interphase barrier elements 124 at the barriers 68, so that bar '72 can move freely in slots 125 in these barriers while blocking the slots. Tie bar 721s united tothe carriers 36 of the outer poles by brackets '75 and to carrier 36 of the center pole by an inverted U member 120 that is staked to its carrier 36.

The trip mechanism 126 normally serves to restrain the actuating mechanisms 66 in the latched condition. The trip device is operable in response to an overload on any of theA circuits controlled by the breaker to etfect release of both actuating mechanisms and thus automatically open all of the movable contacts of the breaker. The trip mechanism is a unitary structure assembled in its own insulating case 128, the trip mechanism being removably secured in the breaker casing as by screws 130. At each pole of the breaker there is provided a thermally responsive trip element or bimetallic strip 132 and magnetically responsive trip means. At each pole a bolt 131 connects strip 118 to a companion terminal 14. The conductor plates or strips 118 provide terminals for the trip mechanism and energizing means for the electromagnetic trip means. The strips 118 have two reverse bends. 134 and 136, there being a straight portion 138 for energizing the magnetically responsive trip means. The loop formed by bend 134 functions as a heater for bimetallic strip 132. means at each pole comprises a core of magnetic material and a companion movable armature 142 which is mounted for movement with respect to the core by means of a guide pin 144 secured to said armature. The armature is biased away from the c ore by means of spring 146 interposed between bracket 146 and collar 148 on pin 144. Portion 138 of the conducting strip passes through the core 140 and forms an energizing windingy for the electromagnetic trip means. A shunt 149 may be used if desired.

The trip mechanism includes a latch 150 at the center pole (FIGS. 5 and 6) pivotally mounted on pivot pin 152 carried by the bracket 154 xed to the outside surface of a Wall of the case 128 by rivets 156. Latch 150Y comprises a pair of laterally spaced walls 158 and 160V interconnected by base wall 162, there being a roller 164 on pin 166 carried by said spaced walls. Latch 1,50 is biased to latching position as shown in FIG. 5 in which it restrains the releasable cradles in latching positions as will be described in detail hereinafter, said latch having an upwardly extending portion 168 which projects through opening 170 provided in case 128. The portion 168 normally engages latch projection 172 of the common trip bar 174 which holds the latch in latching position.

The trip bar 174, of molded insulating material, is adapted to be actuated to elect release of the latch 150 and cradles 94 by any one of the trip devices at any of the poles. The trip bar is mounted on pivot pins 176 received in companion bearings in the projecting arms 178 of bracket 154 (see FIG. l). The arms 178 project through suitable openings provided therefor in the case 128. The trip bar is biased, into latching position and engagement with the latch 150 by spring 180. The heads of the guide pins 144 engage in notches provided therefor in the trip bar to connect the latter to each of the movable armatures 142 for actuation thereby in response to The magnetically responsive trip sudden severe overload currents, adjustably determined. Three adjusting screws 182 are carried by the trip bar, each in a position to be engaged by the free end of a companion bimetallic strip 132 to provide for trip bar actuation on deection of any one of the strips 132 when heated a predetermined amount by overload current sustained long enough for transfer of heat to the bimetallic strip or strips. Each electromagnetic trip means is energized by the current flowing through its corresponding pole and each strip 132 is heated in response to current ilowing through the corresponding pole.

Latch 150 is lightly biased toward a companion stop 19t) of bracket 154 by torsion spring 192 mounted on shaft 194 carried by the laterally spaced arms 196 and 198 of said bracket, one end portion 200 of said spring extending through opening 202' of flange 204 of the latch. The spring 192 has two groups of convolutions longitudinally spaced on shaft 194 and a straight length 206 in operative engagement with part 208 for biasing the same counterclockwise viewing FIG. 5 to thus bias portion 267 toward stop 19t). The part 208 has a pair of laterally spaced arms 210 pivotally mounted on shaft 194 inboard of arms 196 and 19S, said part having an angle shaped part 212 extending between arms 210. One arm 216 is provided with a depending cam part 214 which is arrested by roller 164 of the latch 150 when the latter is blocked by part 172 of the trip bar. Upward bias against part 212 derived from the restrained contact actuating mechanisms, biases part 208 clockwise, and forces cam part 214 to provide clockwise bias (FIG. 5) for latch 150. On trip bar actuation, latch 150 is released for clockwise rotation about its pivot 152 (FIG. 5), by allowing roller 164 to move out of the path of cam part 214 to thereby permit part 203 to rotate clockwise about shaft 194 for release of the actuating mechanisms in the manner to be described. The base 213 of bracket 154 is secured in the casing by a screw 13), the conductor strips 118 being secured in position below base 218 by said screw. The strips 113 are electrically connected to conductor 118 at screw 136 which defines a connector for the center pole. Similar screws, not utilized for mechanical mounting of the trip unit, are used in joining the respective conductors 118 and 118 of those poles.

Operatively engaged with part 208 is a part 216 having center portion 216 engaged below part 212 and arms 220 provided with insulating mounting elements 222 carried by the ends 224 of shaft 194 (see FIG. l). Parts 26S and 216 are coaxial and operate as a unit, so that they may be of one-piece construction if desired. In the illustrated embodiment the arms 220 are of metallic construction and are united to the elements 222 of insulation. Laterally projecting from each of the elements 222 is a pin 226 which is received in a companion elongated slot 22S provided in the inner leg 230 of a frame 232. Such frame 232 is provided at each of the outer poles for each of the cradles of the actuating mechanisms. Each frame 2'32 is pivotally mounted on a shaft 234 carried by a respective frame 76. An elongated latch roller 236 is carried by each frame 232 in the elongated slots 23S thereof, said roller being biased toward the left in FIG. 2 by torsion spring 241D. Slots 23% allow the rollers 236 to be displaced to clear the cradle 94 on relatching the latter after having been tripped, by reset operation of handle 104. From the above it will be apparent that parts 2%, 216, 232 and 236 transmit the upward biasing force (FIG. 2) applied by the cradles 94 to the trip bar part 172. On release of the tripping mechanism at the single trip output point 172 the otherwise independent cradles 94 of the two actuating mechanisms 66 will both be released and will thus open all of the poles of the breaker. The trip unit including all the parts in FIGS. 5 and 6 and all the parts acted upon by frames 232, is removable as a unit when its connections to terminals 14 and conductors 11S are removed, by sliding the trip unit to the right and thus moving pins 226 along, and free of slots 228 in frames 232.

Pursuant to the present invention, only a small fraction of the strong upward biasing force of the cradles 94 is imposed on the trip unit. More particularly, the only force imposed by the actuating mechanisms 66 on the trip mechanism is a low magnitude torsion force required to operate the trip mechanism. The faces 162 of the cradles produce an upward force along a line extending substantially from the point of contact between faces 102 and rollers 236 and the pivotal axes of said rollers that produces only a small clockwise movement of force tending to rotate each frame 232 about its shaft 241 in frame 76. Frames 76 thus provide the reaction to most of the force imposed by mechanisms 66. Frames 76 are well suited to withstand the imposition of such forces, without any unnecessary strain on the removable trip unit. The upward force transmitted along such line will act on an efectively short lever arm (being that from the axis of shaft 240 perpendicularly to the line of force of cradle 94) and will have a low magnitude torsion force component to rotate frames 232 about pivots 234 in a clockwise direction viewing FlG. 2, to supply operating bias for the trip mechanism Thus the force produced by the mechanisms 66 at the faces 102 is subdivided with the bulk of such force being transmitted to frame structure 'i6 with only a small portion of such force being transmitted for imposition on the trip mechanism at pins 226. The bulk of the force at the cradle of each mechanism 66 is absorbed at its own pole.

The coupling between each frame 232 and the removable trip unit is rendered relatively non-critical by the following proportions of the mechanism described. The axis of rotation of frame 232 is at a short radius from the axis of shaft 241 perpendicularly to the upward line of force applied by each cradle part 162 to the roller 236, there being a relatively long radius between the pivotal axis of frame 232 and the axis of pin 226. There is a relatively long radius between the axis of pin 226 and the axis of shaft 194, there being a relatively short radius between the latter and portion 216. Accordingly, slight variations in the position of the trip unit in relation to frames 232 will not result in serious variations in the component of force from cradles 94 that is irnposed on the trip unit. The restraining means for each cradle is coordinated with the other by respective connections to the tripping mechanism to achieve concurrent common release of the cradles on prescribed overload conditions even though the cradles are not joined to each other. Any such interconnection of the cradles would be diicult in View of their lateral separation, their operation at different voltages, and the mechanical forces involved. On the release of latch there is nothing to restrain the release of either of the cradles so that in the event of release of one cradle at some instant of time theoretically in advance of the other, the remaining cradle is also in condition for instant release.

From the above it will be apparent that the illustrative circuit breaker described above has numerous features that give it improved characteristics and increased operating capacity.

Various modifications of this presently preferred embodiment of the invention will readily occur to those skilled in the art, and therefore the invention should be broadly construed in accordance with its full spirit and scope.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. A multi-pole circuit breaker having at each pole a movable contact member and companion Contact means, means fixed to said movable contact members for rigidly coupling said contact members for conjoint movement with respect to their companion contact means between circuit closed and circuit open positions, individual springpowered mechanisms disposed at a plurality of poles for actuating said contact members to said positions, each of said mechanisms including a cradle movable between latched and release positions, and an overcurrent responsive trip mechanism including an individual over-current responsive device in each pole, a common control element controlled by said over-current responsive devices, and an individual latch disposed at each of said springpowered mechanisms and normally arranged to restrain each of said cradles respectively but arranged for release by said common control element, said tripped mechanism being operable to release said cradles for movement to released position in response to fault currents in the circuit of said' trip mechanism.

2. A multipole circuit breaker having a movable contact member and a companion Contact member in each pole, means including an insulated bar fixed to all of the moving contact members for rigidly coupling said movable contact members together for conjoint movement with respect to said companion contact members between closed and open positions, individual overcentering spring actuating mechanisms directly connected to at least two of said movable contact members for actuating said coupled contact members to said positions conjointly whereby the total driving energy of said individual actuating mechanisms is distributed among said movable contact members by said coupling means, said actuating mechanisms including respective individual releasable members movable between restrained positions and released positions for automatic control of said actuating mechanisms, respectively, under over-Current conditions, and an over-current trip mechanism including respective movable parts for releasably holding each of said releasable members in its restraining position in relation to its respective actuating mechanism, a common trip bar normally preventing release movement of said movable parts, and individual over-current responsive means in each pole arranged to etiect release operation of said commonv trip bar.

3. A multi-pole circuit breaker having at each pole movable and companion contact members, means including an insulatedA tie bar xed to said movable contact members for rigidly coupling said movable contact members together for conjoint movement with respect to said companion contact members between circuit closed and circuit open positions, individual spring-powered releasable mechanisms at a plurality of poles for actuating said coupled contact members to said positions whereby the driving energy for said contact members is the summation of the energy of said individual mechanisms and said driving energy is distributed among said contact members, and an overcurrent trip mechanism including an overcurrent responsive device in each pole and common trip means controlled by said devices individually for releasably holding all said mechanisms in circuit closed condition, said common trip means releasing said mechanisms and concomitantly simultaneously opening said movable contact membersin response to fault currents in any of said over-current responsive devices.

4. In a multi-pole circuit breaker having at each pole stationary and movable contact members, means for rigidly coupling said movable contact members for conjoint movement with respect to said stationary contact members between circuit closed and circuit open positions, individual mechanisms at a plurality of poles for actuating said coupled contact members to said positions whereby the driving energy for said Contact members is the summation of the energy of said individual mechanisms, and a trip mechanism including movable latch means for releasably holding said mechanisms in circuit closed condition, said latch means releasing said mechanisms and concomitantly simultaneously opening said movable contact members in response to fault currents in the circuit of said trip mechanism, said trip mechanism including coupling means comprising a pair of torque bars restraining said individual mechanisms, a single latch at a common point for all said poles, and a transverse Q) coupling device restraining said torque bars and restrained; by said single latch.

5. In a multi-pole circuit breaker having at each pole stationary and movable contact members, means for rigidly coupling said movable contact members for conjoint pivotal movement with respect to said stationary contact members between circuit closed and circuit open positions, said coupling means comprising a tie-bar extending transversely ot said movable Contact members adjacent the pivot axis thereof and a supplementary tiebar extending transversely of said movable contact members remote from the pivot axis thereof to achieve equal energy distribution to said movable contact members, individual mechanisms at a plurality of poles for actuating` said coupled contact members to said positions whereby the driving energy for said contact members is the summation of the energy of said individual mechanisms, and a trip mechanism including movable latch means for releasably holding said mechanisms in circuit closed condition, said latch means including individual releasable means in each of said mechanisms biased by said mechanisms in the release direction and means restraining saidl individual releasable means comprising a transversely extending control device, and over-current responsive means in each pole severally arranged to release said transversely extending control device, for releasing said mechanisms and concomitantly simultaneously opening said movable contact members in response to fault currents in the circuit of said trip mechanism.

6. A multi-pole circuit breaker in accordance with claim 3, said circuit breaker including a center pole and two laterally spaced poles, at opposite sidesv of said center pole, wherein only said laterally spaced poles are provided with individualV spring-powered releasable mechanisms as` aforesaid, and anr operating handle for operating said spring-powered mechanisms to open and close, the contacts, said handle being disposed at said center pole and extending to said outer poles.

7. A multi-pole circuit breaker having at each poley movable and companion contact members, means includa ing an insulated tie bar xed to said movable contact members for rigidly coupling said movable contact members for conjoint movement with respect to said companion contact members between circuit closed and circuit open positions, individual mechanisms at a pluralityof poles for actuating said coupled Contact members to said positions whereby the driving energy for said contact members is the summation of the energy of said individual mechanisms. and the driving energy is distributed among said movable contact members by said coupling means, each of the latter including a cradle movable between latched and released positions, individual release means for each cradle disposed at said mechanisms and movable between latched and released positions, common control means for all said release means, and an overcurrent trip mechanism including movable latch means at a single output point for releasably restrainingV said common control means and thereby holding said individual release means in restrained position to thereby releasably hold said mechanisms in circuit closed condition, said latch means at said output point releasing said individual release means and concomitantly said mechanisms to simultaneously open said movable contact memlers in response to predetermined fault currents in the circuit through said trip mechanism at any pole of the breaker. Y

S. In a multi-pole circuit breaker having at each pole stationary and movable Contact members, means for rigidly coupling said movable contact members for conjoint movement with respect to said stationary contact members between circuit closed and circuit open positions, individual mechanisms at a plurality of poles for actuating said coupled contact members to said positions whereby the driving energy for said Contact members is the summation of the energy of said individual mech- 9 Y anisms, each of the latter including a cradle movable between latched and released positions, individual coordinated latch means for each cradle movable between latched and released positions, and a trip mechanism including movable latch means at a single output point for releasably holding said individual latch means in latched position to thereby releasably hold said mechanisms in circuit closed condition, said latch means at said output point releasing said individual latch means and concomitantly said mechanisms to simultaneously open said movable contact members in response to predetermined fault currents in the circuit through said trip mechanism at any pole of the breaker, and means for dividing the force imposed by each mechanism on its corresponding individual latch means through its companion cradle so that the bulk of said force is absorbed at the pole of each mechanism with the remaining force being transmitted to said latch means at said single output point for operating said trip mechanism.

9. In a multi-pole circuit breaker having at each pole stationary and movable contact members, means for rigidly coupling said movable contact members for conjoint movement with respect to said stationary contact members between circuit closed and circuit open positions, individual mechanisms at a plurality of poles for actuating said coupled contact members to said positions whereby the driving energy for said contact members is the summation of the energy of said individual mechanisms, each of the latter including a cradle movable -between latched and released positions, ind-ividual coordinated latch means for each cradle movable between latched and released positions, and a trip mechanism including movable latch means at a single output point for releasably holding said individual latch means in latched position to thereby releasably hold said mechanisms in circuit closed condition, said latch means at said output point releasing said individual latch means and concornitantly said mechanisms to simultaneously open said movable contact members in response to predetermined fault currents in the circuit through said trip mechanism at any po-le of the breaker, said individual latch means comprising roller means pivotally mounted in frame structure at a companion pole, each cradle coacting with companion roller means to produce a force imposed by said mechanisms the bulk of which is transmitted to said frame structure through the pivot of said roller means with the remaining `force being transmitted to said latch means at said output point yfor operating said trip mechanism.

lG. in a multi-pole circuit breaker hav-ing at each pole stationary and movable contact members, means for rigidly coupling said movable contact members for conjoint moveme-nt with respect to said stationary contact members between circuit closed and circuit open positions, individual mechanisms at a plurality of poles for actuating said coupled contact members to said positions whereby the ldriving energy for said contact members is the summation of the energy of said individual mechanisms, and `a trip mechanism including movable latch means for releasably holding said mechanisms in circuit closed condition, said latch means releasing said mechanisms and concomitantly simultaneously opening said movable contact members in response to fault currents in the circuit of said trip mechanism, each mechanim having individual latch means controlled by said trip latch means, and means `for dividing the force imposed by each mechanism on its corresponding individual latch means so that the bulk of said force is absorbed 'at the pole of each mechanism with the remaini-ng `force being transmitted to said trip latch for operating said trip mechamsm.

ll. A multi-pole circuit breaker having at each pole stationary and movable contact members, individual laterally spaced mechanisms at a plurality of poles for actuating said contact members to open and closed positions, each of the actuating mechanisms including a releasable Cit control element, coordinate-d latch means including individual laterally spaced latches cooperating with said releasablc control elements, respectively, said coordinated latch means being movable between latched and released positions, and a trip mechanism including a common trip bar for `all the poles having a single control connection to said coordinated latch means -for releasably holding said latch means in latched position and thereby for releasably holding said mechanisms in circuit closed condition, and an overcurrent responsive element in each pole cooperable `with said trip bar for effecting operation of the latter.

l2. ln a multi-pole circuit breaker having at each pole stationary and movable contact members, means for rigidly coupling said movable contact members for conjoint movement with respect to said stationary contact members between circuit closed and circuit open positions, individual mechanisms at a plurality of poles for actuating said coupled members to said positions whereby the driving energy for said contact members is the summation of the energy of said individual mechanisms, each of the latter including a cradle movable between latched and released positions, individual coordinated latch means for each cradle movable between latched and released positions, and a trip mechanism including movable latch means at a single output point for releasably holding said individual latch means in latched position to thereby releasably hold said mechanisms in circuit closed condition, said latch means at said output point releasing said indivi-dual latch means and concomitantly said mechanisms to simultaneously open said movable contact members in response to predetermined :fault currents in the circuit through said trip mechanism at any pole of the breaker, said individual latch means comprising a roller assembly pivotally mounted in stationary frame structure, each cradle having an inclined end portion coacting with a companion roller of said assembly to produce an upward lforce transmitted along la line extending substantially from the point of contact between said inclined end and roller and the rotational axis of the latter, the pivot axis of said roller assembly being laterally adjacent said line, whereby the bulk of said lforce is transmitted to said stationary frame structure through the pivot axis of said roller assembly with the remaining force being a low magnitude torsion force acting to rotate said roller assembly about the pivot axis thereof for transmission to said latch means at said output point for operating said trip mechanism.

13. ln a multi-pole circuit breaker having at each pole stationary and movable contact members, means for rigidly coupling said movable contact members for conjoint movement -with respect to said stationary contact members between circuit closed and circuit open positions, indivi-dual mechanisms at a plurality of poles for actuating said coupled members to said positions whereby the driving energy for said contact members is the summation of the energy of said individual mechanisms, each of the latter including a cradle movable between latched and released positions, individual coordinated latch means for each cradle movable between latched and released positions, and a trip mechanism including movable latch means at a single output point for releasably holding said individual latch means in latched position to thereby releasably hold said mechanisms in circuit closed condition, said latch means at said `output point releasing said individual latch means and concomitantly said mechanisms to simultaneously open said movable contact members in response to predetermined fault currents in the circuit through said trip mechanism at any pole of the breaker, said individual latch means comprising a roller assembly pivotally mounted in stationary frame structure, each cradle having an inclined end portion coacting with a companion roller of said assembly to produce an upward force transmitted along a line extending substantially from the point of cont-act between said inclined end and roller and the rotational axis of the latter, the pivot axis :of saidroller assembly being laterally adjacent said line, whereby the bulk of said yforce is transmitted to said stationary frame structure .through the pivot taxis of said roller assembly with the remaining force being a low magnitude torsion force acting to rotate said roller assembly about `the pivot axis thereof -for transmission to said latch means at said `output point for openating said trip mechanism, said roller assembly including a pivotal support vfor rotationally mounting said roller, and linkage for operatively connecting each of said supports with said last mentioned `latch means.

14. In a multi-pole circuit breaker having at each pole stationary an-d movable contact members, means for rigidly coupling said movable contact members for conjoint movement with respect to said stationary contact members between circuit closed and circuit open positions, individual mechanisms at a plurality of poles for actuating said coupled members to said positions whereby the driving energy for said contact members is the summation of the energy of said individual mechanisms, each of the latter including a cradle movable between latched and released positions, individual coordinated latch means for each cradle movable between latched and released positions, and a trip mechanism including movable latch means at a single output point for releasably holding said individual latch means in latched position to thereby releasably hold said mechanisms in circuit closed condition, said latch means at said output point releasing said individual latch means and concomitantly said mechanisms to simultaneously open said movable contact members in response to predetermined fault currents in the circuit through said trip mechanism at any pole of the breaker, said individual latch means comprising a roller assembly pivotally mounted in stationary frame structure, each cradle having an inclined end portion coacting with a companion roller of said assembly to produce an upward force transmitted along a line extending substantially from the point of contact between said inclined end and roller and the rotational axis of the latter, the pivot axis of said roller assembly being laterally adjacent said line, whereby the bulk of said force is transmitted to said stationary frame structure through the pivot axis of said roller assembly with the remaining force being a low magnitude torsion force. acting to rotate said roller assembly about the pivot axis thereof for transmission to said latch means at said output point for operating said trip mechanism, said roller assembly including a pivotal support for rotationally mounting said roller, the latter being mounted in aligned elongated slots and being biased therein towards its companion cradle whereby the latter may displace said roller along said slots to relatch the cradle subsequent to tripping thereof.

15. A multi-pole circuit breaker having at each pole movable and companion contact members, said movable Contact members having a common insulated tie bar fixed thereto and being thereby rigidly coupled for conjoint movement vn'th respect to said companion contact members to circuit closed and circuit open positions, individual spring-powered mechanisms as spaced poles for actuating said coupled contact members to said positions, each of said mechanisms having a cradle, and said cradles being independent of each other, individual latch means at each of said spaced poles cooperable with each cradle, respectively, and laterally spaced in accordance therewith, anda trip mechanism including current-responsive means in each pole, current responsive means in each pole, movable latch means at a single output point controlled by said current responsive means, means operatively connecting said individual latch means at said output point and said movable latch means at said outputl point for releasably latching said cradles to thereby hold said mechanisms in circuit closed condition, said, movable latch means releasing said individual latch means and concomitantly said mechanisms to simultaneously open said coupled Contact members in response to predetermined fault currents in any pole of the breaker.

16. A multi-pole circuit breaker having at each pole stationary and movable contact members, said movable contact members being rigidly coupled for conjoint movement with respect to companion stationary contact members to circuit closed and circuit open positions, individual mechanisms at spaced poles for actuating said coupled contact members to said positions, each of said mechanisms having a cradle with said cradles being independent of each other, individual latch means for each cradle, and a trip mechanism including movable latch means at a single output point, means operatively connecting said individual latch means and trip latch means for releasably latching said cradles to thereby hold said mechanisms in circuit closed condition, said trip latch means releasing said individual latch means and concomitantly said mechanisms to simultaneously open said coupled contact members in response to predetermined fault currents in the circuit through said trip mechanism at any pole of the breaker, and means for dividing the force imposed by each mechanism on its correspondingindividual latch means through its companion cradle so that the bulk of said force is absorbed at the pole of each mechanism with the remaining force being transmitted to said latch means at said single output point for operating said trip mechanism.

17. A multi-pole circuit breaker having at each pole movable and companion contact members, said movable contact members having a common insulated tie bar iixed thereto and being thereby rigidly coupled for conjoint movement with respect to said companion contact members to circuit closed and circuit open positions, individual spring-powered mechanisms at spaced poles for actuating said coupled contact members to said positions, each of said mechanisms having a cradle, and said cradles being independent of each other, individual latch means at each of said spaced poles cooperable with each cradle, respectively, and laterally spaced in accordance therewith, and a trip mechanism inclu-ding movable latch means at a single output point, means extending across said pole and operatively connecting said latch means to said movable latch means at said single output point for releasably latching said cradles and for thereby holding said mechanisms releasably in circuit closed condition, said movable latch means releasing said individual latch means and concomitantly releasing said mechanisms to simultaneously open said coupled Contact members in response to predetermined fault currents in the circuit through said trip mechanism at any pole ofthe breaker, said trip mechanism comprising a trip bar common to all of the poles of the breaker, and thermal. means and magnetic means responsive to fault currents at each pole for actuating said trip bar, the latter being operable to releasesaid connecting means in response to faultv current operation of said thermal means or magnetic means at anypole.

18. A multi-pole circuit breaker having: at each pole stationary and movable contact members, said movable contact members being rigidly coupled for conjoint move-l ment with respect to companion stationary contact members to circuit closed and circuit openV positions, individual mechanisms at spacedpoles for actuating said coupled contact members to said positions, each of said mechanisms having a cradle with saidf cradles being inde-y endent of each other, individual latch means for each cradle, and a trip mechanism including movable latch means at a single output point, means operatively connecting said individual latch means and trip latch means .for releasably latching said cradles to thereby hold said mechanisms in circuit closed condition, said trip latch means releasing said individual latch means and concomitantly said mechanisms to simultaneously open said coupled contact members in response to predetermined fault currents in the circuit through said trip mechanism at any pole of the breaker, said individual latch means comprising a pivotal support carrying a roller, the pivot for said support being carried in a rigid frame, each cradle having an inclined end portion coacting with a companion roller to produce a force transmittedalong a line extending substantially from the point of contact between said inclined end and said roller and the rotational axis of the latter, the support pivot being laterally adjacent said line whereby the bulk of said force is transmitted to and absorbed by said rigid frame through said support pivot with the remaining force being a low magnitude torsion force acting to rotate said support about the pivot thereof for transmission to said trip latch means through said connecting means for operating said trip mechanism.

19. A multi-pole circuit breaker having at each pole a movable contact member and a companion contact member, individual mechanisms at a plurality of said poles for actuating said movable contact members to open and closed positions, each of said actuating mechanisms including a releasable control element, an individual restraining means at each of said plurality of poles for releasably restraining each said control element, common control means for all said individual restraining means, and a trip mechanism having a single output control element in control relation to said common control means, said trip mechanism including a common trip bar and individual over-current responsive means in each of said poles of the circuit breaker in control relation to said trip bar, said individual over-current responsive means being operable individually and in any combination to operate said trip bar for releasing said common control means and thereby concurrently releasing said releasable control elements of said poles.

20. A three-pole circuit breaker including three contact arms pivoted on a common axis and arranged side-byside so as to include a center contact arm and two outer contact arms, at least one tie bar iixed to and mechanically uniting said contact arms for movement as a unit about their common pivotal axis, companion contact members cooperable with said movable contact arms, respectively, spring-and-toggle actuating mechanisms assembled respectively to said outer contact arms only, and over-current control means for -automatically causing concurrent contact-opening operation of said actuating mechanisms, said over-current control means including current-responsive elements energized by the currents in each of said movable contact arms, respectively, a common trip bar controlled by said current-responsive elements, and coupling means from said common trip bar to said actuating mechanisms for effecting contact-opening operation of said actuating means under control of said common trip bar.

References Cited in the le of this patent UNITED STATES PATENTS 2,154,703 Sandin Apr. 18, 1939 2,435,305 Grissinger et al Feb. 3, 1948 2,508,178 Lindstrom et al May 16, 1950 2,666,824 Dorfman Jan. 19, 1954 2,922,008 Cellerini et al Ian. 19, 1960 2,981,811 Steven et al Apr. 25, 1961 

1. A MULTI-POLE CIRCUIT BREAKER HAVING AT EACH POLE A MOVABLE CONTACT MEMBER AND COMPANION CONTACT MEANS, MEANS FIXED TO SAID MOVABLE CONTACT MEMBERS FOR RIGIDLY COUPLING SAID CONTACT MEMBERS FOR CONJOINT MOVEMENT WITH RESPECT TO THEIR COMPANION CONTACT MEANS BETWEEN CIRCUIT CLOSED AND CIRCUIT OPEN POSITIONS, INDIVIDUAL SPRINGPOWERED MECHANISMS DISPOSED AT A PLURALITY OF POLES FOR ACTUATING SAID CONTACT MEMBERS TO SAID POSITIONS, EACH OF SAID MECHANISMS INCLUDING A CRADLE MOVABLE BETWEEN LATCHED AND RELEASE POSITIONS, AND AN OVERCURRENT RESPONSIVE TRIP MECHANISM INCLUDING AN INDIVIDUAL OVER-CURRENT RESPONSIVE DEVICE IN EACH POLE, A COMMON CONTROL ELEMENT CONTROLLED BY SAID OVER-CURRENT RESPONSIVE DEVICES, 